<style type="text/css">
			body{
			padding-top:10px;
		}
		.all_bg{
			width:800px;
			height:600px;
			margin:0px auto;
		}
		#allcanvas{
			position: relative;
			width:800px;
			height:600px;
			margin:0px;
		}
		#canvas1{
			position: absolute;
			bottom: 0;
			left:0;
			z-index: 1;
		}
		#canvas2{
			position: absolute;
			bottom: 0;
			left:0;
			z-index: 0;
		}
		</style>